Movable objective lens assembly for an optical microscope and optical microscopes having such an assembly

ABSTRACT

A movable objective lens assembly that includes an infinity-corrected objective lens providing the microscope with an optical field of view. The assembly permits the imaging of a specimen under investigation over an area of the specimen much larger than the field of view of the objective lens without moving the microscope and/or a specimen stage relative to one another. The assembly includes a mirror system and the linearly movable infinity-corrected objective lens. The mirror system includes a plurality of mirrors that provide a folded optical path that allows the objective lens to be moved relative to the specimen without moving the entire microscope. The mirror system and the objective lens are pivotably mounted relative to the rest of the microscope so as to allow the objective lens to be located substantially anywhere within a circular, or circular-sectoral, viewing area.

RELATED APPLICATION DATA

This application is a divisional of U.S. Nonprovisional PatentApplication Ser. No. 12/255,835, filed on Oct. 22, 2008, and entitled“Movable Objective Lens Assembly for an Optical Microscope and OpticalMicroscopes Having Such an Assembly,” which is incorporated herein byreference in its entirety.

FIELD OF INVENTION

The present invention generally relates to the field of opticalmicroscopy. In particular, the present invention is directed to amovable objective lens assembly for an optical microscope and opticalmicroscopes having such an assembly.

BACKGROUND

Optical microscopes are important tools in a variety of analyticalsciences, including, for example, neuroscience and related fields ofstudy. Advanced neurobiology, for instance, uses optical microscopes tounderstand alterations in neural function due to changes in neuronstructure and vice versa. This knowledge plays a crucial role in thedevelopment of novel therapeutic strategies that prevent or combatneurological and neuropsychiatric diseases such as, for example,Alzheimer's disease, schizophrenia, and stroke. To make advances inthese areas, researchers rely on several techniques to understand therelationship between the neuron structure and its corresponding neuralfunction. Electrophysiological (EP) recording, for instance, usesmicroelectrodes to stimulate the electrical activity of a nerve cell.The resultant recordings are often correlated to results of a neuronalreconstruction (NR) techniques, including an NR technique thatautomatedly generates a 3D structural model of a nerve cell (3D-ANR).

Typically, experiments directed to neuron structure combined with EPrecording start with detecting the cell body of a neuron using infrareddifferential interference contrast (IR-DIC) video microscopy. Then,neurons may be identified with a dye (e.g., biocytin or Lucifer yellow)in 300 to 400 μm thick living brain slices during (or at the end of) EPrecording by filling the cells with the dye. Afterwards the brain slicesare usually fixed, cryo-protected, and sectioned on a cryostat into 50μm to 60 μm thick sections to be analyzed separately for neuronmorphology. It may be appreciated that a combined EP/3D-ANR techniquewould permit researchers to complete similar experiments withoutseparate recording and analysis stages. However, although EP recordingand 3D-ANR techniques typically use similar optical microscopes, eachrequires significantly different hardware configurations from the otherthat inhibit a comprehensive combined solution.

SUMMARY OF THE INVENTION

In one implementation, the present disclosure is directed to an opticalmicroscope setup. The optical microscope setup includes a stage forsupporting a specimen, having a first side and a second side spaced fromthe first side, so that each of the first and second sides is viewable;a first optical microscope comprising: a first imaging body having afirst primary optical axis; and a first movable objective lens assemblyhaving a first objective lens located for viewing the first side of thespecimen when the specimen is supported by the stage, the firstobjective lens having a first optical axis and a first field of view,and the first movable objective lens assembly configured to move thefirst objective lens in a direction perpendicular to the first opticalaxis; and a second optical microscope comprising: a second imaging bodyhaving a second primary optical axis; and a second movable objectivelens assembly having a second objective lens located for viewing thesecond side of the specimen when the specimen is supported by the stage,the second objective lens having a second optical axis and a secondfield of view, and the second movable objective lens assembly configuredto move the second objective lens in a direction perpendicular to thesecond optical axis.

In another implementation, the present disclosure is directed to amethod of performing microscopy on a specimen using an opticalmicroscope setup that includes a first objective lens having a firstmagnification power and first field of view and a second objective lenshaving a second magnification power greater than the first magnificationpower and a second field of view, wherein the specimen has a first sideand a second side spaced from the first side and the first objectivelens is located on the first side of the specimen and the secondobjective lens is located on the second side of the specimen. The methodincludes determining a location of a feature of interest based on afirst position of the first objective lens; and based on the determiningof the location of the feature of interest, automatedly moving thesecond objective lens to a second position so that the second field ofview contains at least a portion of the feature of interest.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of illustrating the invention, the drawings show aspectsof one or more embodiments of the invention. However, it should beunderstood that the present invention is not limited to the precisearrangements and instrumentalities shown in the drawings, wherein:

FIG. 1A is a high-level elevational diagram illustrating a conventionalmicroscope system that includes an infinity-corrected objective lens andhas an optical path set at a first length;

FIG. 1B is a high-level elevational diagram of the conventionalmicroscope system of FIG. 1A in which the optical path is set to asecond length greater than the first length of FIG. 1A;

FIG. 2 is a side elevational view of a conventional microscoperetrofitted with a movable objective lens assembly made in accordancewith broad concepts of the present disclosure;

FIG. 3A is a high-level elevational diagram illustrating a microscopesystem that includes a movable objective lens assembly having aninfinity-corrected objective lens, showing the objective lens coaxialwith the primary optical axis of the microscope;

FIG. 3B is a high-level elevational diagram of the microscope system ofFIG. 3A showing the objective lens offset from the primary optical axisof the microscope;

FIG. 4A is a high-level elevational diagram of the movable objectivelens assembly of FIGS. 3A-B showing the objective lens coaxial with thecentral optical axis of the microscope;

FIG. 4B is a high-level plan diagram of the movable objective lensassembly in the state illustrated in FIG. 4A;

FIG. 5A is a high-level elevational diagram of the movable objectivelens assembly of FIGS. 3A-B and 4A-B showing the objective lens offsetrelative to the central optical axis of the microscope;

FIG. 5B is a high-level plan diagram of the movable objective lensassembly in the state illustrated in FIG. 5A;

FIG. 6A is a high-level elevational diagram of the movable objectivelens assembly of FIGS. 3A-B, 4A-B and 5A-B showing the objective lensoffset relative to the central optical axis of the microscope and themirror assembly rotated about the central optical axis;

FIG. 6B is a high-level plan diagram of the movable objective lensassembly in the state illustrated in FIG. 6A;

FIG. 7A is an inverted isometric view of a movable objective lensassembly without a mirror housing illustrating example drive mechanismsfor translating the objective and rotating the mirror assembly;

FIG. 7B is an inverted isometric view of a the movable objective lensassembly of FIG. 7A showing the mirror housing installed;

FIG. 8 is a side elevational view of dual-objective microscope setuphaving first and second movable objective lens assemblies;

FIG. 9 is a plan view of a common scan area of the first and secondmovable objective lens assemblies of FIG. 8; and

FIG. 10 is an inverted isometric view of a movable objective lensassembly without a mirror housing illustrating a two-mirror movableobjective lens assembly that can be used, for example, as either one orboth of the first and second movable lens assemblies of FIG. 8.

DETAILED DESCRIPTION

It is contemplated that a single system configured to permitElectrophysiological (EP) recording and 3D structural modeling of anerve cell (3D-ANR) simultaneously would provide several advantages. Acombined EP/3D-ANR system, for example, would permit repetitivemonitoring of potential alterations in the morphology of differentneurons (filled with different fluorescent dyes) during or as a resultof electric stimulation. Experiments conducted with a combined EP/3D-ANRsystem would also permit the results of neuron reconstruction to be usedto guide the placement of EP probes. This advantage is particularlyimportant when examining connected neurons because IR-DIC does notpermit a nerve fiber (e.g., an axon) to be clearly visualized. Without aclear picture of the entire neuron structure, any analysis using EPrecordings of connected neurons has a relatively low success ratebecause the placement of microelectrodes on adjacent neurons is donerelatively blindly. On the other hand, executing a 3D-ANR simultaneouslywith an EP experiment may provide a neuron model that enables accurateplacement of microelectrodes in experiments, e.g., involving a singledistal synaptic connection formed between different areas (e.g., betweenthe dentate gyms and the CA3 in the hippocampus.)

Most optical microscopes and corresponding microscopy techniques areincompatible with a combined EP/3D-ANR system for studying neuronstructure. More particularly, traditional systems do not meet theaccuracy requirements for successful implementation of a combinedEP/3D-ANR system because they require either (1) moving simultaneouslythe microelectrodes for EP recording and the tissue chamber that carriesthe specimen or (2) moving the entire microscope relative to thespecimen. A movable objective lens assembly made in accordance withconcepts of the present invention, on the other hand, provideshigh-accuracy movements (e.g., increments of less than about 0.25 μm),which are not possible using existing optical microscope technology,such as, for example, an optical microscope having an encoded, closedloop motorized specimen stage.

At a very high level, an optical microscope magnifies an image usingvisible light from a light source that illuminates the underside of aspecimen. An optical microscope includes an optical pathway that permitsvisible light captured by an objective lens (also known as an“objective” or “object lens”) to travel to an imaging lens (or group oflenses), which brings a magnified image into focus on a light detectingapparatus, for example, a human eye, a camera, a sensor, and anycombination thereof. Both the imaging lens and objective lens include aseries of refractive lenses that work in conjunction with one another togenerate a magnified image having a predetermined magnification level.

The magnification level defines a corresponding field-of-view thatdescribes the diameter of a circle of visible light. Because thefield-of-view becomes smaller as the level of magnification increases,it follows that the visible portion of a specimen will also be reduced.Accordingly, to view other portions of the specimen without reducing themagnification level (and thereby increasing the field-of-view), somemicroscopes are equipped with a mechanical stage that moves the specimenrelative to the field-of-view. Other microscopes that include astationary stage require that the specimen be repositioned on the stagein order to place a different portion of the specimen in thefield-of-view. Still other microscopes include a specimen that isfixedly mounted in a manner that requires the microscope to bere-positioned to move the field-of-view. None of these options maintainsthe necessary magnification for certain procedures, such as EP/3D-ANR,while providing an accurate positioning mechanism for moving a specimenwithin a field-of-view. A movable objective lens assembly made inaccordance with novel concepts of the present disclosure, however, cansimultaneously satisfy both of these requirements.

Referring now to the drawings, by way of background FIGS. 1A-Billustrate basic components of a typical conventional opticalimaging-type microscope 100. Microscope 100 includes an imaging lens 104and an image sensor 108, the combination of which captures a magnifiedimage. Alternatively, and as those skilled in the art know, image sensor108 may be replaced with, or accompanied by, a suitable eyepiece (notshown) that allows a user to view the image directly. Conventionalmicroscope 100 also includes an objective lens 112 positioned at a focaldistance f from a tissue specimen 116. FIG. 1A shows microscope 100 ashaving an optical path 120 formed between the backside of objective lens112 and imaging lens 104. Comparatively, FIG. 1B shows microscope 100 ashaving an optical path 120′ that is longer than optical path 120 of FIG.1A by a distance d₁. Although optical path 120′ of FIG. 1B is longerthan optical path 120 of FIG. 1A, by using an infinity-correctedobjective lens for objective lens 112, in the scenario of FIG. 1B sensor108 will capture a magnified image of tissue specimen 116 that issubstantially similar in quality to the magnified image of the tissuespecimen captured by the sensor in the scenario of FIG. 1A, except for aminimal loss of intensity due to refraction caused by air within theoptical path and sub-microscopic particles, which can be neglected forpurposes of the examples provided herein. FIGS. 1A-B illustrate theconcept that when using infinity-corrected optics, hereinfinity-corrected objective lens 112, the image formed at image sensor108 essentially does not vary as a function of the length of the opticalpath, here, each of optical paths 120, 120′.

In contrast to conventional microscope 100 of FIGS. 1A-B, FIG. 2illustrates a microscope system 200 (in this example an upright opticalbright-field-type microscope system) made in accordance with some of thebroad concepts of the present disclosure. In this example, microscopesystem 200 includes an optical bright-field microscope 204 (such asmicroscope 100 of FIG. 1, but without conventional objective 112)outfitted with a movable objective lens assembly 208, which has anobjective lens 212 that is movable laterally relative to the primaryoptical axis 216 of microscope 204. This lateral movement is effected bylateral translation of objective lens 212 toward and away from primaryoptical axis 216 or a combination of this lateral translation withrevolution of the objective lens about the primary optical axis. Beforedescribing movable objective lens assembly 208 in more detail, for thesake of context and completeness, components of microscope 204 are firstdescribed.

Microscope 204 includes an imaging body 220 and base 224 that, as thoseskilled in the art will recognize, provides primary optical axis 216 andcontain various optic, mechanical, electrical and electromechanicalsystems for enabling various functionality and operations of themicroscope, including functionality and operation well known in the art,such as focusing, specimen illumination and image acquisition, amongothers. In this example, microscope system 200 has an imaging device 228(e.g., video camera) mounted to body 220 of microscope 204 so that itsimage sensor (not shown) is located orthogonally to primary optical axis216. Microscope system 200 also includes an imaging eyepiece 232 forviewing of essentially the same image available to imaging device 228.As those skilled in the art will readily understand, microscope 204includes an internal beamsplitter (not shown) for providing the splitoptical paths to imaging device 228 and eyepiece 232. Microscope 204also includes a stage 236 for supporting a specimen (not shown), such asa specimen mounted to a conventional microscope slide. One or moreilluminators, in this example a single bright-field condenser 240, ismounted to base 224. Depending on the extent of movability of objectivelens 212 and the nature of the illuminator(s), the illuminator(s) may befixed relative to base 224 or, alternatively, may be movable relative tobase in concert with the objective lens so that the light emitted fromthe illuminator(s) remains in proper alignment with the objective lens.

As those skilled in the art will appreciate, although the presentexample is directed to a bright field optical microscope, in otherembodiments the illuminator(s) provided may be for another type ofoptical microscopy, such as oblique illumination microscopy, dark fieldmicroscopy, dispersion staining microscopy, phase contrast microscopy,differential interference contrast microscopy and fluorescencemicroscopy. In addition, microscope 204 may have another configuration,such as an inverted configuration, and it need not be a conventionalmicroscope that is retrofitted with a movable objective lens assemblysuch as assembly 208, but rather it may include a designed-in movableobjective lens that provides the same functionality as assembly 208.

As will be seen relative to FIGS. 3A-6B, movable objective lens assembly208 allows a user to move objective lens 212 essentially to any locationwithin a circular “scan area” centered on primary optical axis 216. Abenefit of the movability of objective lens 212 includes the ability tomove the field-of-view of the objective lens without having to movestage 236. This permits microscope 204 to be used for efficient scanningof relatively larger areas of a specimen, for example, for creatinghigh-power images of a specimen, or portion thereof, that aresignificantly large than the field-of-view of objective lens 212.

In this example, movable objective lens assembly 208 is fixedly securedto microscope 204 (here, base 224) by a suitable support 244. Althoughsupport 244 is shown as being attached to base 224, in other embodimentsit may be attached to imaging body 220. Assembly 208 includes a mirrorhousing 248, which contains a plurality of mirrors (not shown in FIG. 2,but described in detail below and shown throughout the remainingfigures), and an optical tube 252 extending between imaging body 220 ofmicroscope 204 and the mirror housing. Mirror housing 248 and opticaltube 252 provide a substantially sealed optical path from objective lens212 to imaging body 220 that inhibits dust and other contaminants fromreaching the insides of the mirror housing and the optical tube. Asmentioned above, objective lens 212 is translationally movable relativeto primary optical axis 216 using two degrees of freedom, namely,translation parallel to a radial line 258 radiating normally fromprimary optical axis 216 and revolution about the primary optical axis.The movability of objective lens 212 is described below in detail.

FIGS. 3A-B illustrate basic components of an optical microscope system300 made in accordance with novel concepts of the present disclosure,such as microscope system 200 of FIG. 2. Like microscope 100 of FIGS.1A-B in this example microscope 300 of FIGS. 3A-B includes an imaginglens 304 and an image sensor 308 positioned along an optical path 312.However, unlike microscope 100 of FIGS. 1A-B, microscope 300 of FIGS.3A-B further comprises a movable objective lens assembly 316 thatincludes an infinity-corrected objective lens 320, which, like objectivelens 112 of FIGS. 1A-B may be located a focal distance f from a specimen324. As will be described in more detail in connection with FIGS. 4A-B,5A-B and 6A-B below, objective lens 320 is mounted in a manner thatpermits it to move over a desired scan area 400 (FIGS. 4B, 5B and 6B)that is larger than the field-of-view provided by the objective lensitself.

Referring to FIGS. 4A-B, 5A-B and 6A-B, and also to FIGS. 3A-B, the sizeof scan area 400 may correspond to, or otherwise encompass, the extentof specimen 324 (FIGS. 3A-B) or a smaller portion thereof, depending onthe size of the specimen and the range of movement provided to objectivelens 320 by movable objective lens assembly 316. Such movement permitsobjective lens 320 to be positioned so as to place its correspondingfield-of-view over differing portions of specimen 324 without changingthe magnification of microscope 300 (e.g., by switching the objectivelens with a higher power objective lens) and without moving the tissuespecimen and/or the entire microscope relative to one another. As thoseskilled in the art will readily appreciate, scan area 400 (FIG. 4B)enabled by movable objective lens assembly 316 will be circular in shapewhen the assembly is mounted so that it is rotatable a full 360° about aportion 312A of optical path 312 between objective lens assembly 316 andimaging lens 304. (Portion 312A of optical path 312 in this examplewould be coincident with primary optical axis 216 of imaging body 220 ofFIG. 2.) With such a configuration, those skilled in the art willappreciate that the position of objective lens 320 anywhere within scanarea 400 may be identified using polar coordinates (here, (d, θ)),wherein d is the horizontal centerline offset distance shown in FIG. 3Bbetween the optical axis 328 of the objective lens and portion 312A ofoptical path 312, and θ (FIG. 4B) is the angular rotation of movableobjective lens assembly 316 about that same portion of optical path 312relative to an established radial baseline (not shown, but could be anysuitable baseline that may, for example, be dependent on whatevermechanism is used to provide the movable objective lens assembly withits rotatability).

In this example embodiment, movable objective lens assembly 316 alsoincludes a mirror assembly 332 positioned generally above objective lens320 and including four mirrors 332A-D. As discussed in more detailbelow, mirrors 332A-C are stationary relative to the mirror assembly andmirror 332D is movable relative to the mirror assembly in conjunctionwith objective lens 320. Although movable objective lens assembly 316may be fixedly attached directly to microscope 300, it is contemplatedthat other designs would permit mirror assembly 332 to be executed inany manner that establishes its location with respect to portion 312A ofoptical path 312 without being attached directly to the microscope. Inthe present example, mirror 332A may be considered to be locatedco-axially with portion 312A of optical path 312 and mirrors 332B-C arelocated in an offset relationship to portion 312A defined by a distanced₂. Mirror 332D, on the other hand, is mounted in a manner that permitsit to move with respect to portion 312A of optical path 312 in tandemwith objective lens 320 in directions toward and away from mirror 332C.

As will be understood from FIGS. 3A-B, 4A-B, 5A-B and 6A-B, mirrorassembly 332 is configured to allow objective lens 320 to be movedradially (relative to portion 312A of optical path 312) whilemaintaining the proper optical path 312 between movable objective lensassembly 316 and imaging lens 304 (FIGS. 3A-B) that allows the desiredimage to form at image sensor 308. Four-mirror mirror assembly 332accomplishes this by folding optical path 312 in a manner that providesa leg 336 (FIG. 3B) that is perpendicular to portion 312A of opticalpath 312 and has a length that varies as objective lens 320 is movedradially. As seen by comparing FIGS. 3A and 3B, when objective lens 320is moved by a distance d₃ (FIG. 3B) away from portion 312A of opticalpath 312, the total length of the optical path increases by distance d₃.Because objective lens 320 is infinity-corrected, this increase inlength of optical path 312 does not significantly impact the quality andcharacter of the image available at image sensor 308. In an alternativeembodiment having four mirrors arranged similarly to mirrors 332A-D, theother horizontal leg 340 (FIG. 3B) could be the one with variablelength. In that embodiment, mirror 332A of FIGS. 3A-B, 4A-B, 5A-B and6A-B could be made fixed relative to portion 312A of optical path 312and mirrors 332B-D fixed together and to objective lens 320 so as tomove in concert with the objective lens relative to that portion of theoptical path.

In view of the foregoing, it will be appreciated that, other thingsbeing equal, mirror assembly 332 as illustrated in FIG. 3A has opticalpath 312 that is longer than optical path 120 described in connectionwith FIG. 1A by a distance of 2d₂. In contrast, as seen in FIG. 3Bmoving objective lens 320 and mirror 332D from a first position P₀ tosecond position P₁ further elongates optical path 336 by a distance d₃.Accordingly, while image sensor 308 and imaging lens 304 have not movedin a manner similar to FIGS. 1A-B, optical path 336 is increased inlength by 2d₂+d₃ without changing the magnification or focus of themicroscopic image of specimen 324 because of the infinity-correctednature of objective lens 320. In a combined EP/3D-ANR system, in oneexample of an instantiation of microscope 300 of FIGS. 3A-B, 4A-B, 5A-Band 6A-B containing movable objective lens assembly 316 in accordancewith the present disclosure, mirror assembly 332 may include a totalaxial travel distance of less than about 1 cm, based on an incrementalaccuracy discussed above that is less than about 0.25 μm.

FIGS. 4A-B, 5A-B and 6A-B illustrate movable objective lens assembly 316of microscope 300 of FIGS. 3A-B in more detail and so as to illustratethe movability of objective lens 320 not only in a linear manner, butalso in a radial manner. As mentioned above, this movability allowsobjective lens 320 to be located as needed to allow its field of view tobe placed anywhere within scanning area 400. As shown in each of FIGS.4A-B, 5A-B and 6A-B, movable objective lens assembly 316 includes amirror-assembly support 404 that supports objective lens 320 and mirrorassembly 332 so as to permit the objective lens and mirror assembly topivot around a rotational axis 408 that is co-axial with portion 312A ofoptical path 312. In the present example, mirror-assembly support 404 iscircular in shape. In one example, mirror assembly 332 may berotationally fixed relative to mirror assembly support 404, and thesupport may include a rack or other feature (not shown) that a pinion,gear or other driving means may engage so as to pivot the support andmirror assembly in concert with one another. In another example, acircular embodiment of mirror-assembly support 404 may act as a fixedsupport rail on which mirror assembly 332 slides, rolls or otherwisemoves along the rail when pivoted, for example, by a driveactuator/mechanism (not shown) located near portion 312A of optical path312. Although mirror-assembly support 404 is shown as circular in thisembodiment, it is contemplated that other embodiments of the support 404may have a different shape, such as, for example, square, rectangular,oval, etc., with the ultimate design being dependent on a number offactors, including design choice, space constraints and type of drivesystem, among others. In yet other embodiments, mirror-assembly support404 may be integrated into a housing. For example, such a housing may begenerally circular in shape, fixed relative to microscope 300 with whichmovable objective lens assembly 316 is attached, and enclose a region inwhich mirror assembly 332 pivots during use. In still yet otherembodiments, mirror-assembly support 404 need not be used, as mirrorassembly 332 may be supported in a manner similar to the manner shown inFIG. 2, such as by optical tube 252, which is fixed to microscope 204.In such a case, the rotational drive actuator/mechanism could also besupported by optical tube 252 or support 244.

Referring again to FIGS. 3A-B, 4A-B, 5A-B and 6A-B, in this examplemovable objective lens assembly 316 is configured to permit 360°rotation of objective lens 320 and mirror assembly 332 about rotationalaxis 408, which again is coaxial with portion 312A of optical path 312of microscope 300 (FIGS. 3A-B). This rotation, in conjunction with asecond degree-of-freedom of axial translation of objective lens 320 andmirror 332D along a translation axis 412, allows the objective lens tobe positioned so as to place its corresponding field-of-view ontovirtually any portion of scan area 400. Using, for example, a polarcoordinate (d, θ) control scheme, the position of objective lens 320 andmirror 332D can essentially be defined for every location within scanarea 400. Importantly, a movable objective lens assembly made inaccordance with concepts of the present disclosure and having thisfield-of-view-enlarging capability can readily permit the scanning of arelatively large area of a tissue or other specimen, or an entirespecimen, without having to move a microscope stage and/or a microscoperelative to one another. The increase in observable specimen area canimprove the execution of certain procedures, such as the proceduresdiscussed above.

In this connection, positions P₀, P₂, P₃ of, respectively, FIGS. 4A-B(P₀), 5A-B (P₂) and 6A-B (P₃) illustrate three differing positions intowhich mirror 332D and objective lens 320 are moveably positioned inrelation to scan area 400. As explained above in the context of FIGS.3A-B, when objective lens 320 is an infinity-corrected optic, althoughthe optical path varies in length as between the differing positions ofFIGS. 4A-B, 5A-B and 6A-B (here, positions P₀, P₂, P₃, respectively),the quality and character of the magnified images received by imagesensor 308 will not be substantially compromised. Comparing FIGS. 4B and5B with one another, it can be readily appreciated that position P₂ ofFIG. 5B can be achieved from position P₀ of FIG. 4B simply bytranslation of objective lens 320 and mirror 332D along translation axis412 of mirror assembly 332. Comparing FIGS. 5B and 6B with one another,it can be appreciated that position P₃ can be achieved from position P₂by rotating mirror assembly 332, for example, by the angle θ₁ shown.Consequently, position P₃ of FIG. 6B can be achieved from position P₀ ofFIG. 4B by performing, for example, an axial translation of objectivelens 320 and mirror 332D from first position P₀ to second position P₂ ofFIG. 5B and a rotation to third position P₃.

FIGS. 7A-B show a movable objective lens assembly 700 having afour-mirror mirror assembly 704 and infinity-corrected objective lens708 that are substantially the same as, respectively, mirror assembly332 and objective lens 320 of FIGS. 3A-B. FIGS. 7A-B illustrate anexample actuation scheme for moving objective lens 708 (andcorresponding mirror 712) of mirror assembly 704) linearly and movingthe entire mirror assembly rotationally so as to effect the two degreesof freedoms discussed above relative to FIGS. 2, 3A-B, 4A-B, 5A-B and6A-B. In this example, mirror 712 and objective lens 708 are supportedby two externally threaded screws 716A-B, which are rotatably mounted toa set of screw supports 720A-D fixed to a circular disk 724. Screws716A-B are oppositely threaded and threadingly engage correspondingrespective ones of a pair of mirror supports 728A-B. A motor or otherrotational actuator 732 engages both screws 716A-B so that when theactuator rotates, the screws turn in opposing directions relative to oneanother. As screws 716A-B are turned, mirror 712 and objective lens 708move linearly parallel to the screws so as to provide the pure lineardegree of freedom to the objective lens. With suitably pitched thread onscrews 716A-B and/or suitable gearing of rotational actuator 732, themovement of objective lens 708 can be very finely controlled as neededto suit a particular application.

Disk 724 is rotatably mounted to a disk support 736 that allows the diskto rotate about its concentric center 740. When mounted to a microscope,such as microscope 204 of FIG. 2, disk support 736 may be fixedlysecured to the microscope in any suitable manner so that its concentriccenter 740 coincides with the primary optical axis of the microscope,such as primary optical axis 216 in FIG. 2. For example, in the contextof microscope 204 of FIG. 2, disk support 736 may be secured to opticaltube 252, support 244, or both. Referring again to FIGS. 7A-B, as showndisk 724 is rotated by a motor or other rotational actuator 744, whichmay be supported by an actuator support 748 fixedly secured to disksupport 736. Depending on the gearing of rotational actuator 744 and thediameter of disk 724, the rotational degree of freedom of movableobjective lens assembly 700 may be as finely controlled as needed.Rotational position can be sensed using any suitable transducer (notshown), such as position sensor/encoder. The sensed position can beused, for example, in a feedback control system (not shown) forcontrolling the pivoting mirror assembly 704 during operation. FIG. 7Bshows assembly 700 as including a mirror housing 752 having an elongatedopening 756 for accommodating the translational movement of objectivelens 708. To provide a dust seal that inhibits dust from entering theinterior of housing 752, opening 756, on either side of objective lens708, is filled by a suitable closure 760, such as a roll-up-typeclosure.

FIG. 8 illustrates another microscope setup 800 that incorporatesvarious broad concepts of the present disclosure. Microscope setup 800includes an upright microscope system 802 and an inverted microscopesystem 804, both of which are fluorescence-type microscopes in thisexample. It is noted, however, that in other embodiments each of uprightand inverted microscope system 802, 804 may be of another type, such asone of the other types noted above relative to microscope system 200 ofFIG. 2. It is further noted that in other embodiments, upright andinverted microscopes need not be of the same type, depending on thedesired application of microscope setup 800.

Upright microscope system 802 includes an upright microscope 806 and afirst movable objective lens assembly 808. Similarly, invertedmicroscope system 804 includes an inverted microscope 810 and a secondmovable objective lens assembly 812. In this example, upright microscope806 includes a first imaging body 814 that provides a first primaryoptical axis 816 and contains optics for 1) directing a firstfluorescent light beam 818 toward first movable objective lens assembly808, 2) splitting light 820 reflected along the primary optical pathfrom the first movable objective assembly to each of a first eyepiece822 and a first imaging device 824 and 3) forming an image from thelight reflected along the primary optical path. In this connection,first imaging body 814 includes at least one imaging lens (or group oflenses) (not shown, but can be similar to imaging lens 304 of FIGS.3A-B) fixed relative to the imaging body. Inverted microscope 810includes a second imaging body 826 that provides a second primaryoptical axis 828 and contains optics for 1) directing a secondfluorescent light beam 830 toward second movable objective lens assembly812, 2) splitting light 832 reflected along the primary optical pathfrom the second movable objective assembly to each of a second eyepiece834 and a second imaging device 836 and 3) forming an image from thelight reflected along the primary optical path. In this connection,second imaging body 826 includes at least one imaging lens (or group oflenses) (not shown, but can be similar to imaging lens 304 of FIGS.3A-B) fixed relative to the imaging body. Upright microscope 806 alsoincludes a base 838 that supports and raises first imaging body 814relative to inverted microscope system 804.

Microscope setup 800 also includes a stage 840 that supports a specimen842, for example, a tissue specimen, and further includes amicromanipulator 844, which can be used for a number of purposes, suchas injecting a dye (e.g., a fluorescence dye) into the specimen.Micromanipulator 844 may be movably mounted to stage 840 via a suitablesupport 846. In one example, support 846 may be movably engaged withstage 840 so as to be movable around the stage (either manually orautomatically or a combination of both). Support 846 may also, oralternatively, be configured to provide the manipulated item, here aprobe 848, with one or more degrees of movement, either manually orautomatically or a combination of both. In this connection, microscopesetup 800 may include a controller 850 (here represented as a centralcontroller but could also be a distributed system or a combinationthereof) for controlling various functionality and/or operations of thevarious components of microscope setup, including controlling automaticmovement of support 846 and/or the manipulated item in response tocontrolling input from a user. Controller 850 may be implemented in anumber of ways as will be understood by those skilled in the art. Forexample, controller 850 may be implemented using a computer, such as ageneral purpose personal computer, among others. Such controlling inputmay be input via any suitable user interface, that may include any oneor more of a graphical user interface, touchscreen, soft controls, hardcontrols (such as a joystick, mouse, tablet/puck, etc.) and voiceactivated controls, among others. Controller 850 may also be used tocontrol functionality and/or operation of first and second movableobjective lens assemblies 808, 812 so as to move correspondingrespective first and second objective lenses 852, 854, for example, asdescribed below.

In this example, each of first and second movable objective lensassembles 808,812 are of a two-mirror type in which two mirrors 856, 858(first assembly 808), 860, 862 (second assembly) enable thetranslatability of a corresponding objective lens 852, 854 along thecorresponding respective translation axes 864, 866 of the first andsecond movable objective lens assemblies. In this example, each of firstand second movable mirror assemblies is arranged so that it can be moved(at least at its theoretical limits), in this example, substantiallyanywhere within first and second circular sectors 900, 904 (FIG. 9),lying in corresponding respective planes perpendicular to, respectively,first and second primary optical axes 816, 828. These circular sectors900, 904 are located so that they overlap a substantial amount and, inthis example, so that they overlap at a common scan area 908 wherein, asdescribed below, specimen 842, or portion thereof, is placed during useof dual-microscope setup 800.

In one example use of dual-microscope setup 800, first and secondobjective lenses 852, 854 are of differing magnifying powers. In thisexample, one of first and second objective lenses 852, 854, say secondobjective lens 854, being used as a low-power “scouting” lens and theother, here, first objective lens 852, being used as a high-power“detail” lens. During an example usage session, second objective lens854 is used to scan specimen 842, or a portion thereof, at a relativelylow power while a user (not shown) and/or image recognition software868, for example, is seeking, or looking for, one or more items ofinterest, such as one or more physical features. In the example of ahuman user, the user may view the current field of view of the secondobjective lens either by looking through second eyepiece 834 orobserving the field of view on a video display 870 as captured by secondimaging device 836. The user may control the movement of secondobjective lens 854 via controller 850 using any suitable type of userinterface. Under full automation, controller 850 may move secondobjective lens 854, for example, according to a predetermined scoutingpath.

Following identification of a feature (location) of interest (again,either by a human user or recognition software 868, or both), in thisexample higher-power first objective lens 852 is moved so that its fieldof view encompasses all or part of the feature (location) of interest.In this manner, the higher-power first objective lens 852 can be usedfor higher-power imaging of the feature (location) of interest. In amanner similar to lower-power second objective lens 854, a user may usefirst eyepiece 822 on first microscope 806 to view the feature(location) of interest at the higher power of first objective lens 852.Alternatively, or in addition, the user may view an image of the fieldof view of first objective lens 852 on display 870 or another display.Of course, images (still or moving) of the fields of view of one, theother, or both, of first and second objective lenses 852, 854 ascaptured by imaging devices 824, 836 may be stored in any suitablemanner, such as on an optical disk, magnetic disk or any other suitabletype of storage device (not shown).

In this example, higher-power first objective lens 852 may be moved to afeature (location) of interest in a completely automated manner. Forexample and referring to FIG. 9, first and second coordinate systems912, 916 may be established, respectively, to describe the locations offirst and second objective lenses 852, 854 within their correspondingrespective sectors 900, 904 of movement. Because of the rotationalnature of each of first and second movable objective assemblies 808,812, each of first and second coordinate systems 912, 916 may be thepolar coordinate systems shown. Each of these “local” coordinate systems912, 916 can be used directly by controller 850 (FIG. 8) in controllingthe linear and rotational movements of the respective first or secondmovable objective assembly 808, 812, for example, via correspondingdrive mechanisms (not shown, but see the examples in FIG. 10). Referringto FIGS. 8 and 9, with 1) a first known local coordinate system foraccurately determining the position of second movable objective lens 854(here coordinate system 916) relative to second primary optical axis, 2)a known location and orientation of second primary optical axis 828relative to first primary optical axis 816, 3) as needed, the locationof the feature (location) of interest within the field of view of thesecond objective lens and 4) a second known local coordinate system foraccurately positioning first objective lens 852 relative to the firstprimary optical axis (here coordinate system 912), controller 850 canreadily be able to determine the coordinates of the feature (location)of interest in the first coordinate system.

Controller 850 can then be used to move first objective lens 852 so thatits field of view encompasses the feature (location) of interest. Thoseskilled in the art will appreciate that there may be other ways ofmoving first objective lens 852 to the necessary position to view thefeature (location) of interest initially found using second objectivelens 854, for example, by using a global coordinate system that isglobal to both first and second microscope systems 802, 804. It is notedthat locating of higher-power first objective lens 852 as a function ofthe location of the feature (location) of interest as determined vialower-power second objective lens 852 may be enhanced by an auto-focusfeature. An example auto-focus feature may use depth of focusinformation from lower-power second objective lens 854 in combinationwith one or more reference points, axes, etc. (such as a perpendiculardistance between the horizontal plane containing horizontal optical axis866 of second movable lens assembly 812 and the upper surface of a slidesupporting specimen 842) fixed relative to both of first and secondmicroscope system 802, 804. As those skilled in the art will appreciate,with such information, and also depth-of-focus information forhigher-power first objective lens 852, controller 850 can determine theproper depth of focus of the first objective lens from the depth offocus of lower-power second objective lens 854. The algorithms needed toperform calculations and to control one or more auto-focus actuators forimplementing such auto-focusing features are within the ordinary skillof an artisan in the relevant technical field.

In other embodiments of a dual-microscope setup similar todual-microscope setup 800 of FIG. 8 the functions of the two microscopesmay be reversed, with the upright microscope providing the lower-powerobjective lens and the inverted microscope providing the higher-powerobjective lens. In yet other embodiments, the magnification of bothobjective lenses of the first and second movable objective lensassemblies may be of the same power. In such embodiments, theseobjectives may be used to independently, or coordinatedly, view thediffering sides of the specimen.

As discussed above, each of first and second movable objective lensassemblies 808, 812 in this example is a two-mirror type assembly thatuses two mirrors. FIG. 10 illustrates a two-mirror movable objectivelens assembly 1000 that could be used for either one or both of firstand second movable objective lens assemblies 808, 812. In this example,two-mirror assembly 1000 includes a fixed mirror 1004 and a movablemirror 1008 that is movable in translation relative to the fixed mirror.Fixed mirror 1004 is fixedly secured to a pivotable base 1012 that ispivotable relative to a fixed base 1016 about a pivot axis 1020 thatpasses through the fixed mirror 1004. When fixed base 1016 of two-mirrorassembly 1000 is fixedly secured to a microscope, such as either firstmicroscope 806 or second microscope 810 of FIG. 8, pivot axis 1020 wouldbe positioned to coincide with the primary optical axis of thatmicroscope. In the context of first microscope 806 of FIG. 8, thatprimary optical axis is axis 816. Similarly, in context of secondmicroscope 810 of FIG. 8, that primary optical axis is axis 828.

Two-mirror assembly 1000 also includes an infinity-corrected objectivelens 1024 fixed relative to movable mirror 1008. Objective lens 1024 maybe of any magnification power needed to suit a particular purpose. Ofcourse, in the example of FIG. 8, two instantiations of two-mirrorassembly 1000 (FIG. 10) for use as first and second movable objectivelens assemblies of FIG. 8 would have differing magnification powers.Pivotable base 1012 may be pivoted relative to fixed base 1016 using afirst actuator 1028, for example a stepper motor. In other embodiments,another type of actuator may be used, such as a linear actuator. Inaddition, the actuator provided may either be manually actuated orpowered. If first actuator 1028 is of a powered type, it can further becontrolled by a suitable controller. In the example of FIG. 8,controller 850 could control the operation of first actuator 1028according to any suitable control algorithm.

In this example, movable mirror 1008 is linearly movable relative topivotable base 1012 via a rail 1032 fixed to the pivotable base and asecond actuator 1036 fixed to the movable mirror. Second actuator 1036may be a powered actuator, for example, a stepper motor, and may becontrolled by a controller, such as controller 850 of FIG. 8, inconjunction with first actuator 1028 to properly position objective lens1024 at a desired position relative to a specimen, for example, specimen842 of FIG. 8. Second actuator 1036 may include a pinion 1040 thatengages a corresponding rack (not shown) on rail 1032. In alternativeembodiments, second actuator 1036 may be a manually operated actuator,such as a micrometer-type screw system. Another type of actuator, suchas a linear actuator, for example, a piezoelectric linear motor, can beused to impart the linear movement of movable mirror 1008 relative topivotable base. It is noted that two-mirror movable objective lensassembly 1000 is shown with its protective structures, for example,housing and closure(s), removed. However, it should be understood thatmovable objective lens assembly 1000 could include a housing andclosure(s) similar to housing 752 and closure 760 of FIG. 7B.

Referring again to FIGS. 2 and 8, it is seen that these figuresillustrate not only two different types of movable objective lensassemblies (assembly 208 being a four-mirror assembly and both ofassemblies 808, 812 being two-mirror assemblies), but also two differentimplementations of these assemblies. In FIG. 2, movable objective lensassembly 208 is used to move corresponding objective lens 212 over acircular scan area (see, e.g., scan area 400 of FIG. 4B) having itsgeometric center along primary optical axis 216. However, in FIGS. 8 and9, each of first and second movable lens assemblies 808, 812 are used tomove corresponding respective objective lenses 852, 854 generally withincircular sectors 900, 904 having their arc centers along thecorresponding respective primary optical axes 816, 828. While theseimplementations are shown, it is noted that all combinations andpermutations of the differing types of movable objective lens assembliesand differing implementations are possible. For example, four-mirrorassembly 208 can be used in a setup that scans only in a circularsector, and each of two-mirror assemblies 808, 812 can be used in setupsthat scan circular scan areas. Regarding the latter, however, it isnoted that, unlike a four-mirror assembly and due to the physicallimitations of a two-mirror assembly, the objective lens of a two mirrorassembly cannot be located so that its optical axis coincides with theprimary optical axis of the microscope it is attached to. In addition,it is noted that regardless of the type of the movable objective lensassembly or its implementation, the optics of the various setups do notrequire use of any image rotators. Furthermore, while specific examplesof drive systems are shown for each of the four- and two-mirrorassemblies shown in FIGS. 7A and 10, it is noted that the drive systemsof these two assemblies are interchangeable with one another and withother drive systems that may occur to those skilled in the art.

Exemplary embodiments have been disclosed above and illustrated in theaccompanying drawings. It will be understood by those skilled in the artthat various changes, omissions and additions may be made to that whichis specifically disclosed herein without departing from the spirit andscope of the present invention.

1. An optical microscope setup, comprising: a stage for supporting aspecimen, having a first side and a second side spaced from the firstside, so that each of the first and second sides is viewable; a firstoptical microscope comprising: a first imaging body having a firstprimary optical axis; and a first movable objective lens assembly havinga first objective lens located for viewing the first side of thespecimen when the specimen is supported by said stage, said firstobjective lens having a first optical axis and a first field of view,and said first movable objective lens assembly configured to move saidfirst objective lens in a direction perpendicular to said first opticalaxis; and a second optical microscope comprising: a second imaging bodyhaving a second primary optical axis; and a second movable objectivelens assembly having a second objective lens located for viewing thesecond side of the specimen when the specimen is supported by saidstage, said second objective lens having a second optical axis and asecond field of view, and said second movable objective lens assemblyconfigured to move said second objective lens in a directionperpendicular to said second optical axis; wherein: said first movableobjective lens assembly comprises a first mirror system that includes: afirst plurality of mirrors, including: a first mirror fixed along saidfirst primary optical axis and pivotable thereabout, said first mirrorfor directing light from a third optical axis perpendicular to saidfirst optical axis to along said first primary optical axis; and asecond mirror fixed relative to said first objective lens and movable ina direction parallel to said third optical axis, said second mirror fordirecting light from said first field of view along a fourth opticalaxis parallel to said third optical axis; and a first support supportingsaid first plurality of mirrors so as to allow said first plurality ofmirrors to pivot about said first primary optical axis; and said secondmovable objective lens assembly comprising a second mirror system thatincludes: a second plurality of mirrors, including: a third mirror fixedalong said second primary optical axis and pivotable thereabout, saidthird mirror for directing light from a fifth optical axis perpendicularto said second optical axis to along said second primary optical axis;and a fourth mirror fixed relative to said second objective lens andmovable in a direction parallel to said fifth optical axis, said fourthmirror for directing light from said second field of view along a sixthoptical axis parallel to said fifth optical axis; and a second supportsupporting said second plurality of mirrors so as to allow said secondplurality of mirrors to pivot about said second primary optical axis. 2.An optical microscope setup according to claim 1, wherein said third andfourth optical axes are coaxial with one another and said fifth andsixth optical axes are coaxial with one another.
 3. An opticalmicroscope setup according to claim 1, wherein said first mirror systemconsists essentially of four mirrors such that said first mirror systemincludes a fifth mirror and a sixth mirror working cooperatively withone another so as to fold said fourth optical path along said thirdoptical path.
 4. An optical microscope setup according to claim 3,wherein said fifth and sixth mirrors are fixed relative to said firstmirror and said second mirror is movable along said fourth optical path.5. An optical microscope setup according to claim 1, wherein said firstoptical microscope is an upright microscope and said second opticalmicroscope is an inverted microscope.
 6. An optical microscope setupaccording to claim 1, wherein said first and second primary optical axesare substantially parallel to one another and spaced from one another.7. An optical microscope setup according to claim 6, said firstmicroscope is configured so that said first objective lens is movableonly in a first circular sector having a central angle less than 180°and said second microscope is configured so that said second objectivelens is movable only in a second circular sector having a central angleless than 180°, said first and second circular sectors extendinggenerally toward each other away from corresponding respective ones ofsaid first and second primary optical axes.
 8. An optical microscopesetup according to claim 1, wherein said first and second objectivelenses have intentionally differing magnifying powers.
 9. An opticalmicroscope setup according to claim 1, wherein said first objective lensis a relatively low power scouting lens for use in identifying withinthe specimen a feature of interest, and said second objective lens is arelatively high-power detail lens for imaging the feature of interest ata higher power.
 10. An optical microscope setup according to claim 9,further comprising a controller programmed to move said second objectivelens to the feature of interest in response to identification of thefeature of interest using said first objective lens.
 11. A method ofperforming microscopy on a specimen using an optical microscope setupthat includes a first objective lens having a first magnification powerand first field of view and a second objective lens having a secondmagnification power greater than the first magnification power and asecond field of view, wherein the specimen has a first side and a secondside spaced from the first side and the first objective lens is locatedon the first side of the specimen and the second objective lens islocated on the second side of the specimen, the method comprising:determining a location of a feature of interest based on a firstposition of the first objective lens; and based on said determining ofthe location of the feature of interest, automatedly moving the secondobjective lens to a second position so that the second field of viewcontains at least a portion of the feature of interest.
 12. A methodaccording to claim 11, wherein the optical microscope setup furtherincludes: a first imaging body; and a second imaging body fixed relativeto the first imaging body; wherein the first objective lens is movablerelative to the first imaging body and the second objective lens ismovable relative to the second imaging body; the method including priorto said determining of the location of the feature, moving the firstobjective lens to the first position by moving the first objective lensrelative to the first imaging body; wherein said automated moving of thesecond objective lens to the second position includes moving the secondobjective lens relative to the second imaging body.
 13. A methodaccording to claim 12, wherein: the first imaging body has a firstprimary optical axis; the second imaging body has a second primaryoptical axis; the first objective lens has a third optical axis; thesecond objective lens has a fourth optical axis; the moving of the firstobjective lens relative to the first imaging body includes, when thethird optical axis is parallel to, and spaced from, the first opticalaxis, pivoting the first objective lens about the first optical axis;and the moving of the second objective lens relative to the secondimaging body includes, when the fourth optical axis is parallel to, andspaced from, the second optical axis, pivoting the second objective lensabout the second optical axis.
 14. An optical microscope setup,comprising: a stage for supporting a specimen, having a first side and asecond side spaced from the first side, so that each of the first andsecond sides is viewable; a first optical microscope comprising: a firstimaging body having a first primary optical axis; and a first movableobjective lens assembly having a first objective lens located forviewing the first side of the specimen when the specimen is supported bysaid stage, said first objective lens having a first optical axis and afirst field of view, and said first movable objective lens assemblyconfigured to move said first objective lens in a directionperpendicular to said first optical axis; and a second opticalmicroscope comprising: a second imaging body having a second primaryoptical axis; and a second movable objective lens assembly having asecond objective lens located for viewing the second side of thespecimen when the specimen is supported by said stage, said secondobjective lens having a second optical axis and a second field of view,and said second movable objective lens assembly configured to move saidsecond objective lens in a direction perpendicular to said secondoptical axis; wherein: said first and second primary optical axes aresubstantially parallel to one another and spaced from one another; andsaid first microscope is configured so that said first objective lens ismovable only in a first circular sector having a central angle less than180° and said second microscope is configured so that said secondobjective lens is movable only in a second circular sector having acentral angle less than 180°, said first and second circular sectorsextending generally toward each other away from corresponding respectiveones of said first and second primary optical axes.
 15. An opticalmicroscope setup according to claim 14, wherein: said first movableobjective lens assembly comprises a first mirror system that includes: afirst plurality of mirrors, including: a first mirror fixed along saidfirst primary optical axis and pivotable thereabout, said first mirrorfor directing light from a third optical axis perpendicular to saidfirst optical axis to along said first primary optical axis; and asecond mirror fixed relative to said first objective lens and movable ina direction parallel to said third optical axis, said second mirror fordirecting light from said first field of view along a fourth opticalaxis parallel to said third optical axis; and a first support supportingsaid first plurality of mirrors so as to allow said first plurality ofmirrors to pivot about said first primary optical axis; and said secondmovable objective lens assembly comprising a second mirror system thatincludes: a second plurality of mirrors, including: a third mirror fixedalong said second primary optical axis and pivotable thereabout, saidthird mirror for directing light from a fifth optical axis perpendicularto said second optical axis to along said second primary optical axis;and a fourth mirror fixed relative to said second objective lens andmovable in a direction parallel to said fifth optical axis, said fourthmirror for directing light from said second field of view along a sixthoptical axis parallel to said fifth optical axis; and a second supportsupporting said second plurality of mirrors so as to allow said secondplurality of mirrors to pivot about said second primary optical axis.16. An optical microscope setup according to claim 15, wherein saidthird and fourth optical axes are coaxial with one another and saidfifth and sixth optical axes are coaxial with one another.
 17. Anoptical microscope setup according to claim 15, wherein said firstmirror system consists essentially of four mirrors such that said firstmirror system includes a fifth mirror and a sixth mirror workingcooperatively with one another so as to fold said fourth optical pathalong said third optical path.
 18. An optical microscope setup accordingto claim 17, wherein said fifth and sixth mirrors are fixed relative tosaid first mirror and said second minor is movable along said fourthoptical path.
 19. An optical microscope setup according to claim 14,wherein said first optical microscope is an upright microscope and saidsecond optical microscope is an inverted microscope.
 20. An opticalmicroscope setup according to claim 14, wherein said first and secondobjective lenses have intentionally differing magnifying powers.
 21. Anoptical microscope setup according to claim 14, wherein said firstobjective lens is a relatively low power scouting lens for use inidentifying within the specimen a feature of interest, and said secondobjective lens is a relatively high-power detail lens for imaging thefeature of interest at a higher power.
 22. An optical microscope setupaccording to claim 21, further comprising a controller programmed tomove said second objective lens to the feature of interest in responseto identification of the feature of interest using said first objectivelens.
 23. An optical microscope setup, comprising: a stage forsupporting a specimen, having a first side and a second side spaced fromthe first side, so that each of the first and second sides is viewable;a first optical microscope comprising: a first imaging body having afirst primary optical axis; and a first movable objective lens assemblyhaving a first objective lens located for viewing the first side of thespecimen when the specimen is supported by said stage, said firstobjective lens having a first optical axis and a first field of view,and said first movable objective lens assembly configured to move saidfirst objective lens in a direction perpendicular to said first opticalaxis; and a second optical microscope comprising: a second imaging bodyhaving a second primary optical axis; and a second movable objectivelens assembly having a second objective lens located for viewing thesecond side of the specimen when the specimen is supported by saidstage, said second objective lens having a second optical axis and asecond field of view, and said second movable objective lens assemblyconfigured to move said second objective lens in a directionperpendicular to said second optical axis; wherein said first objectivelens is a relatively low power scouting lens for use in identifyingwithin the specimen a feature of interest, and said second objectivelens is a relatively high-power detail lens for imaging the feature ofinterest at a higher power.
 24. An optical microscope setup according toclaim 23, wherein: said first movable objective lens assembly comprisesa first mirror system that includes: a first plurality of mirrors,including: a first mirror fixed along said first primary optical axisand pivotable thereabout, said first mirror for directing light from athird optical axis perpendicular to said first optical axis to alongsaid first primary optical axis; and a second mirror fixed relative tosaid first objective lens and movable in a direction parallel to saidthird optical axis, said second mirror for directing light from saidfirst field of view along a fourth optical axis parallel to said thirdoptical axis; and a first support supporting said first plurality ofmirrors so as to allow said first plurality of mirrors to pivot aboutsaid first primary optical axis; and said second movable objective lensassembly comprising a second mirror system that includes: a secondplurality of mirrors, including: a third mirror fixed along said secondprimary optical axis and pivotable thereabout, said third mirror fordirecting light from a fifth optical axis perpendicular to said secondoptical axis to along said second primary optical axis; and a fourthmirror fixed relative to said second objective lens and movable in adirection parallel to said fifth optical axis, said fourth mirror fordirecting light from said second field of view along a sixth opticalaxis parallel to said fifth optical axis; and a second supportsupporting said second plurality of mirrors so as to allow said secondplurality of mirrors to pivot about said second primary optical axis.25. An optical microscope setup according to claim 24, wherein saidthird and fourth optical axes are coaxial with one another and saidfifth and sixth optical axes are coaxial with one another.
 26. Anoptical microscope setup according to claim 24, wherein said firstmirror system consists essentially of four mirrors such that said firstmirror system includes a fifth mirror and a sixth mirror workingcooperatively with one another so as to fold said fourth optical pathalong said third optical path.
 27. An optical microscope setup accordingto claim 26, wherein said fifth and sixth mirrors are fixed relative tosaid first mirror and said second mirror is movable along said fourthoptical path.
 28. An optical microscope setup according to claim 23,wherein said first optical microscope is an upright microscope and saidsecond optical microscope is an inverted microscope.
 29. An opticalmicroscope setup according to claim 23, wherein said first and secondprimary optical axes are substantially parallel to one another andspaced from one another.
 30. An optical microscope setup according toclaim 29, wherein said first microscope is configured so that said firstobjective lens is movable only in a first circular sector having acentral angle less than 180° and said second microscope is configured sothat said second objective lens is movable only in a second circularsector having a central angle less than 180°, said first and secondcircular sectors extending generally toward each other away fromcorresponding respective ones of said first and second primary opticalaxes.
 31. An optical microscope setup according to claim 23, whereinsaid first and second objective lenses have intentionally differingmagnifying powers.
 32. An optical microscope setup according to claim23, further comprising a controller programmed to move said secondobjective lens to the feature of interest in response to identificationof the feature of interest using said first objective lens.